[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status

During some profiling I noticed that default_idle causes a lot of
memory traffic. I think that is caused by the atomic operations
to clear/set the polling flag in thread_info. There is actually
no reason to make this atomic - only the idle thread does it
to itself, other CPUs only read it. So I moved it into ti->status.

Converted i386/x86-64/ia64 for now because that was the easiest
way to fix ACPI which also manipulates these flags in its idle
function.

Cc: Nick Piggin <npiggin@novell.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 11 insertions, 12 deletions

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index 9e819eb68229..7c5729d1fd06 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -764,9 +764,9 @@ static int apm_do_idle(void)
         int     idled = 0;
         int     polling;
 
-        polling = test_thread_flag(TIF_POLLING_NRFLAG);
+        polling = !!(current_thread_info()->status & TS_POLLING);
         if (polling) {
-                clear_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status &= ~TS_POLLING;
                 smp_mb__after_clear_bit();
         }
         if (!need_resched()) {
@@ -774,7 +774,7 @@ static int apm_do_idle(void)
                 ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax);
         }
         if (polling)
-                set_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status |= TS_POLLING;
 
         if (!idled)
                 return 0;
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 525432e3fef7..6946b06e2784 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -102,7 +102,7 @@ void default_idle(void)
         local_irq_enable();
 
         if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
-                clear_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status &= ~TS_POLLING;
                 smp_mb__after_clear_bit();
                 while (!need_resched()) {
                         local_irq_disable();
@@ -111,7 +111,7 @@ void default_idle(void)
                         else
                                 local_irq_enable();
                 }
-                set_thread_flag(TIF_POLLING_NRFLAG);
+                current_thread_info()->status |= TS_POLLING;
         } else {
                 while (!need_resched())
                         cpu_relax();
@@ -174,7 +174,7 @@ void cpu_idle(void)
 {
         int cpu = smp_processor_id();
 
-        set_thread_flag(TIF_POLLING_NRFLAG);
+        current_thread_info()->status |= TS_POLLING;
 
         /* endless idle loop with no priority at all */
         while (1) {
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 355d57970ba3..b045c279136c 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -272,9 +272,9 @@ cpu_idle (void)
         /* endless idle loop with no priority at all */
         while (1) {
                 if (can_do_pal_halt)
-                        clear_thread_flag(TIF_POLLING_NRFLAG);
+                        current_thread_info()->status &= ~TS_POLLING;
                 else
-                        set_thread_flag(TIF_POLLING_NRFLAG);
+                        current_thread_info()->status |= TS_POLLING;
 
                 if (!need_resched()) {
                         void (*idle)(void);
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index d6fa41459c80..b596837a1527 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -110,7 +110,7 @@ static void default_idle(void)
 {
         local_irq_enable();
 
-        clear_thread_flag(TIF_POLLING_NRFLAG);
+        current_thread_info()->status &= ~TS_POLLING;
         smp_mb__after_clear_bit();
         while (!need_resched()) {
                 local_irq_disable();
@@ -119,7 +119,7 @@ static void default_idle(void)
                 else
                         local_irq_enable();
         }
-        set_thread_flag(TIF_POLLING_NRFLAG);
+        current_thread_info()->status |= TS_POLLING;
 }
 
 /*
@@ -202,8 +202,7 @@ static inline void play_dead(void)
  */
 void cpu_idle (void)
 {
-        set_thread_flag(TIF_POLLING_NRFLAG);
-
+        current_thread_info()->status |= TS_POLLING;
         /* endless idle loop with no priority at all */
         while (1) {
                 while (!need_resched()) {